MicroRNAs (miRNAs) are a class of small noncoding RNAs that negatively regulate their mRNA targets by binding with imperfect complementarity in the 3′-untranslated region. Largely unrecognized before 2001, it is now clear that miRNA represent a widely conserved mechanism of post-transcriptional gene regulation. In mammals, regulatory roles have been identified for miRNA in many areas of biology, pointing to miRNA as an exciting new class of therapeutic targets with broad applications.
Much information about miRNA function to date has been obtained through inhibition of their function with anti-miRNA oligonucleotides. As miRNAs are short (18-24 nucleotides) nucleic acids, anti-miRNA oligonucleotides targeting miRNAs using Watson-Crick basepairing is a way to achieve specific pharmacological inhibition of miRNA function.